DESCRIPTION: The purpose of this renewal application is to map the gene for non-DYTI idiopathic torsion dystonia (ITD), non-chromosome 9-linked torsion dystonia. Families will be ascertained and sampled and screened for linkage with markers in the 9q region. 9q linked families will be shared with Xandra Breakefield, who has separate funding to clone the 9q gene. Clinical and ancestral information will be also assessed on all participating families for clinical comparisons and phenotype/genotype correlations. Non DYT1 families will then be subjected to a genomic screen. Ascertainment will concentrate on late onset families. Families will be stratified by clinical subtypes in order to define homogenous linkage screening categories and heterogeneity will be assessed. Once linkage is established, they will fine map the disease locus, perform linkage disequilibrium studies in an attempt to positionally clone the linked locus as well as undertake phenotype genotype correlations both DYT1 and non-DYT1 loci. All the studies proposed will be carried out by the same members of the highly productive long standing collaborative group.